Raul Martinez's showdown against Rodrigo Guerrero for the vacant IBF super flyweight title appears set for Sept. 24.

Sean Gibbons, a matchmaker for Tijuana-based Zanfer Promotions, said the bout will take place in Mexicali, Mexico, on the undercard of the WBO super bantamweight title fight between Jorge Arce (57-6-2, 44 KOs) and Simphiwe Nongqayi (16-1-1, 6 KOs).

The fight, a rematch of an IBF title eliminator Nov. 20 won by Martinez, had been targeted for Sept. 17 on the Julio Cesar Chavez Jr.-Ronald Hearns undercard.

But Chavez was forced to withdraw because of an injury. The card was canceled.

"It's never bad to have a little more time to prepare," Martinez said. "We'll be ready."

Straight shot

Chavez withdraws: An injury to Chavez Jr. has forced the son of the legendary Mexican champion to pull out of his Sept. 17 middleweight title defense against Hearns, ESPN.com is reporting.

Chavez (43-0-1, 30 KOs) suffered a cut on his right hand two weeks ago when he accidently caught it in a ceiling fan during training. He needed two stitches to close the wound, his manager, Billy Keane, said, adding that he felt the laceration would not heal fully in time for the fight.

Chavez was supposed to meet Hearns (26-2, 20 KOs), the son of all-time great Thomas Hearns, in Chavez's hometown of Culiacan, Mexico.

Lou DiBella, Hearns' promoter, disputes the injury claim, suggesting that Chavez was having trouble making weight.

Local notebook

Oct. 1 update: A change has been made to the Oct. 1 pro boxing card at La Villita, as one San Antonio fighter has replaced another in the main event.

Eloy Suarez (11-12-1, 5 KOs) now is set to take on Hector Camacho Jr. (53-4-1, 28 KOs) in a 10-round junior middleweight bout.

Camacho was scheduled to meet Golden Johnson (25-8-3, 18 KOs) atop the nine-bout card. But Johnson reportedly could not agree to terms with the promoter, Zeferino Entertainment of Kingman, Ariz., and declined the fight.

The bout was part of Golden Boy Promotions' "Fight Night Club" show at the Club Nokia, televised on Fox Sports Net.

S.A. trio: Three San Antonio fighters fought on separate cards last weekend.

Steven Moreno (4-1, 4 KOs) won his fourth straight bout, all by knockout. He needed just 52 seconds to knock out Bobby Pickett (0-5) of Texarkana, Ark., in a four-round heavyweight bout Aug. 20 in Houston.

Nicholas Calamaco (0-3) lost to Julio Cesar Rangel (7-4, 5 KOs) of Mexico City by fourth-round TKO (2:07) in a middleweight bout Aug. 20 in Dallas.

And Robert Ledesma (0-1), making his pro debut, was stopped by Ray Ximenez (4-0, 1 KO) of Dallas in the second round (1:34) of a four-round bout Aug. 19 in Fort Worth.